HP Laptop Blank Screen LED Error Codes.

Code descriptions

Use the following table to learn about the meaning of a code that your computer may encounter.
Code typeNumber of Blinks or BeepsComponent Being CheckedConditionPossible solution(s)
AC power adapter LEDConstantly onPower adapterOK. Power is being supplied.None. The power adapter is likely not the problem.
AC power adapter LEDConstantly offPower adapterPower is not being suppliedTry a different power outlet.

Replace power adapter.
AC power adapter LEDContinuous blinkingPower adapterInsufficient powerTry a different power outlet.

Replace power adapter.
Caps Lock/Num Lock1CPUCPU not functionalReseat replace CPU.

Service
Caps Lock/Num Lock2BIOSBIOS corruption failureRestore BIOS from onboard backup (jumpers)

Service
Caps Lock/Num Lock3MemoryMemory module error not functionalReseat memory modules (see next section).

Test memory from UEFI or BIOS.

Replace bad memory modules.

Service
Caps Lock/Num Lock4GraphicsGraphics controller not functionalService
Caps Lock/Num Lock5System boardGeneral system board failureService
Caps Lock/Num Lock6BIOSBIOS authentication failureRestore BIOS from onboard backup (jumpers)

Service
BeepVariesVariesVariesReseat memory modules (see next section).

Service

For more detail on the exact code, search the Internet for "beep code" and the manufacturer of your BIOS - such as AMI or Award.

Click on the link to get HP laptop Blank Screen LED Error Codes for HP Compaq laptops from HP support site.
 HP laptop Blank Screen LED Error Codes